y\'=1/x^2

（x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3.（x-y)(x+y)-(x+y)^2+2y(y-x),其中x=1,y=3.（x-y)(x+y)-(x+y)^2+2y(y-x)

2y(x+二分之一y)-[(x+y)(x-y)+2y(y+x)],其中|x-1|=22y(x+二分之一y)-[(x+y)(x-y)+2y(y+x)],其中|x-1|=22y(x+二分之一y)-[(x+

x-y/x-x+y/y-(x+y)(x-y)/y²y/x=2x-y/x-x+y/y-(x+y)(x-y)/y²y/x=2x-y/x-x+y/y-(x+y)(x-y)/y²

已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1

若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值若2/x-1/y=3,求[y

x+2y=2x+y+1=7x-y求：2x-y?x+2y=2x+y+1=7x-y求：2x-y?x+2y=2x+y+1=7x-y求：2x-y?x+2y=7x-y-->6x=3y-->y=2x(1)x+2y

设x,y满足约束条件x+y>=1,x-y>=-1,2x-y设x,y满足约束条件x+y>=1,x-y>=-1,2x-y设x,y满足约束条件x+y>=1,x-y>=-1,2x-y画出x+y>=1,x-y>

设x,y满足约束条件x+y>=1,x-y>=-1,2x-y设x,y满足约束条件x+y>=1,x-y>=-1,2x-y设x,y满足约束条件x+y>=1,x-y>=-1,2x-y首先救出每两条直线交点,共

二元一次方程：2(x+y)-(x-y)=3(x+y)-2(x-y)=1二元一次方程：2(x+y)-(x-y)=3(x+y)-2(x-y)=1二元一次方程：2(x+y)-(x-y)=3(x+y)-2(x

(3x-y)^2+(3x+y)(3x-y),x=1,y=-2(3x-y)^2+(3x+y)(3x-y),x=1,y=-2(3x-y)^2+(3x+y)(3x-y),x=1,y=-21041012290

2(x+y)-3(x-y)=16(x+y)+(x-y)=512(x+y)-3(x-y)=16(x+y)+(x-y)=512(x+y)-3(x-y)=16(x+y)+(x-y)=512(x+y)-3(x

{3(x+y)-4(x-y)=4{x+y/2+x-y/6=1{3(x+y)-4(x-y)=4{x+y/2+x-y/6=1{3(x+y)-4(x-y)=4{x+y/2+x-y/6=13(x+y)-4(x

{6(x-y)-7(x+y)=21{2(x-y)-5(x+y)=-1{6(x-y)-7(x+y)=21{2(x-y)-5(x+y)=-1{6(x-y)-7(x+y)=21{2(x-y)-5(x+y)=

变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y变量x,y满足约束条件,x+y>=3,x-y>=-1,2x-y-1

(x-y)^2+(x+y)(x-y)其中X=3Y=-1(x-y)^2+(x+y)(x-y)其中X=3Y=-1(x-y)^2+(x+y)(x-y)其中X=3Y=-1(x-y)^2+(x+y)(x-y)=

(x-y)/(x+y)=3求(3x-2y-1)/(x+y-5)(x-y)/(x+y)=3求(3x-2y-1)/(x+y-5)(x-y)/(x+y)=3求(3x-2y-1)/(x+y-5)(x-y)/(

若x*x+y*y=x+y-1/2,求x,y的值如题若x*x+y*y=x+y-1/2,求x,y的值如题若x*x+y*y=x+y-1/2,求x,y的值如题

先化简,再求值:y(x-y)-x(x+y)/x²-y²÷x²+y²/x+y,其中x=2,y=-1先化简,再求值:y(x-y)-x(x+y)/x²-y&

1-[(x-y)/(x+2y)]÷[(x+y)(x-y)/(x+2y)²]1-[(x-y)/(x+2y)]÷[(x+y)(x-y)/(x+2y)²]=1-[(x-y)/(x+2y)

（2x-y)(y+2x)-(2y+x)(x+2y)其中x=-1y=2（2x-y)(y+2x)-(2y+x)(x+2y)其中x=-1y=2（2x-y)(y+2x)-(2y+x)(x+2y)其中x=-1y